Field of the Invention
The present invention relates to a nasal interface for providing a flow of respiratory gases to a user.
Description of the Related Art
Nasal interfaces for providing a flow of gases to a user include interfaces having nasal outlets with pillows that provide a seal at a user's nostrils, and nasal cannulae interfaces where the nasal outlets are nasal prongs for insertion into a user's nostrils. A typical nasal cannula interface includes a plenum portion and entry tubing or a manifold section (symmetric or single sided) and a pair of open-ended prongs which protrude from the plenum or manifold and extend into the nostrils of the user in use to supply the patient with gases. Generally, but not always, the prongs of a nasal cannula are sized and shaped so that they do not seal against the nostrils of a patient. Nasal cannulae are used because these are advantageous in certain situations. For example, in circumstances where a patient is breathing normally, but requires supplementary gases such as oxygen. The existing market for nasal cannula includes devices suitable for delivery of gases in the 0 to 5 liters per minute range. These devices are typically supported by a double entry lumen of small diameter (2-3 mm range) that supply both sides of the nasal cannula and provides even or equal airflow to each nasal prong. These devices typically deliver dry gas flows of between 0 to 5 liters per minute, when the patient is self-breathing, and it is not necessary for the cannula prongs to seal against the nares of a user. A user will entrain the supplementary gases provided from the cannula along with atmospheric air as they inhale normally.
An example of a nasal cannula interface that seals against the nostrils is the Nasal-Aire interface made by Innomed, where gases are provided to the interface and the prongs by conduits or hoses that extend from the users nose across their cheeks, over their ears and around the back of their head.
WO 2008/060295 describes a non-sealing cannula that includes nasal prongs. There are many configurations described. The nasal prongs are adapted to deliver air to a patient's nasal passage and the different embodiments of prongs described include various external features, and may include passages that pass through the wall of the prongs to allow sensors or similar to measure the properties of gases in the prongs.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide an improved nasal interface or to at least provide the industry or public with a useful choice.